In the manufacture of x-ray tubes or other electronic devices which require the use of high voltages for their successful operation, specially designed high voltage cable terminations are used for connecting the device to a cable which supplies the required voltage. For example, an x-ray device comprises an x-ray generator or tube mounted in an oil-filled housing which includes a pair of female receptacles to which the ends of the tube are electrically connected. To each receptacle is connected a mating termination which is fixed to the end of a high voltage cable. Thus, high voltage electrical energy is supplied to the tube from a suitable external energy source. An example of a cable termination structure is found in U.S. Pat. No. 2,522,572.
Contemporary designs of high voltage cable terminations are basically electrically and mechanically sound. However, in several areas improvements are necessary. For example, the termination is complex to fabricate and requires a potting operation in which the assembly is filled with a liquid filling compound which requires several hours to harden. The potting operation is designed to drive air from the insides of the assembly, adhere to the prepared cable ends, and yield an electrically stable assembly.
Electrical breakdown does occasionally occur, however, due to the fact that the filling process has never been perfected to the point of always assuring a satisfactory bond. This deficiency paves the way for possible electrical creepage along the surface of the cable, between the cable and filling compound, and eventually to ground.
Known cable terminations are also relatively large and rigid and require a mating receptacle in the housing to also be large and to therefore occupy a relatively large volume of the housing. The cable receptacles in the housings are located in horns which are protruding portions extending from an otherwise cylindrical housing which conveniently may be approximately eighteen inches long and about six inches in diameter.
Termination of high voltage cables into housing horns takes up considerable space external to the housing to the extent that the relationship of the horns and other portions of the housing such as an x-ray port window in the housing is of prime importance in field installations. As a result of the needs of various installations, complex rotating sections have been built into x-ray housings to allow for proper orientation of the horns and port window.
Where x-ray systems are to be provided in hospital installations, it is required that high voltage cables be placed within conduit and sometimes pulled considerable distances. The outer diameter of known terminations prevents them from being inserted into and drawn through conduits and this usually requires that the end of the cable be terminated after the cable has been drawn through the conduit. As mentioned previously, the complexity in the structure and in the assembly process itself makes it difficult and time consuming to perform the termination in the field and, as a result, quality is often lacking in field-terminated cable end structures. Electrical failure usually occurs in a poor quality high voltage cable termination.